Using Assurance Cases to Guide Verification and Validation of Research Software

Research software engineers can use Assurance Cases (ACs) to guide Verification and Validation (VnV) efforts. An AC is a structured argument that a property like correctness holds. We illustrate how ACs can guide VnV activities via a case study of software for automatically extracting the 3D segmentation of the aorta from medical images of the chest. The AC argument suggests that the following evidence is required: comparison to a pseudo-oracle; traceability between requirements, design, code and tests; review of all artifacts by a domain expert with proper credentials; documentation of input assumptions; and a warning that only qualified people should use the software. The case study highlights that code is not the only artifact of interest for building confidence and that making an explicit distinction between software and user responsibilities is useful.